What is the square root of 100v^4

It is impossible to find the square root of numbers with variables, because they are undefined, the closest you can get is √100v^4

The square root is 10v^2. This is because the square root of 100 is 10 and the square root of the pronumeral with the exponent of 4 is v^2, as the square root of an exponent is that divided by 2 (4/2=2)